Datasheet

Bits 3:0 – ID[3:0] Generic Clock Generator Selection
These bits select the generic clock generator that will be configured or read. The value of the ID bit group
versus which generic clock generator is configured is shown in the next table.
A power reset will reset the GENCTRL register for all IDs, including the generic clock generator used by
the RTC. If a generic clock generator ID other than generic clock generator 0 is not a source of a “locked”
generic clock or a source of the RTC generic clock, a user reset will reset the GENCTRL for this ID.
After a power reset, the reset value of the GENCTRL register is as shown in the next table.
GCLK Generator ID Reset Value after a Power Reset
0x00 0x00010600
0x01 0x00000001
0x02 0x00010302
0x03 0x00000003
0x04 0x00000004
0x05 0x00000005
0x06 0x00000006
0x07 0x00000007
0x08 0x00000008
After a user reset, the reset value of the GENCTRL register is as shown in the table below.
GCLK
Generator ID
Reset Value after a User Reset
0x00 0x00010600
0x01 0x00000001 if the generator is not used by the RTC and not a source of a 'locked'
generic clock
No change if the generator is used by the RTC or used by a GCLK with a WRTLOCK as
one
0x02 0x00010302 if the generator is not used by the RTC and not a source of a 'locked'
generic clock
No change if the generator is used by the RTC or used by a GCLK with a WRTLOCK as
one
0x03 0x00000003 if the generator is not used by the RTC and not a source of a 'locked'
generic clock
No change if the generator is used by the RTC or used by a GCLK with a WRTLOCK as
one
0x04 0x00000004 if the generator is not used by the RTC and not a source of a 'locked'
generic clock
No change if the generator is used by the RTC or used by a GCLK with a WRTLOCK as
one
SAM D21 Family
GCLK - Generic Clock Controller
© 2018 Microchip Technology Inc.
Datasheet Complete
DS40001882D-page 134